Logon to a website and the use of jQuery and JSON - javascript

I have a information screen solution where a computer has a locally stored HTML page which loads an external template (including the functional Javascript etc.) into the browser.
The reason that this page is local is that if the computer is started when there is no network connection, or e.g. the server is down, it will retry over a period of time.
However, sometimes this computer needs to logon, so I pass the logon credentials and a cookie is based back.
<script type="application/javascript">
url = "http://192.168.1.27:9000/carousel/1/template?user=test&password=test";
function loadTemplate() {
$( "#error" ).html("Loading...");
$( "#message" ).html("");
$('body').load(url, function( response, status, xhr ) {
if ( status == "error" ) {
$( "#error" ).html("<h3>Sorry but there was an error:<br/></font></h3>" + " Description: " + xhr.statusText + " (" + xhr.status + ")");
}
});
}
</script>
However, on subsequent requests (which come as part of this template load) this cookie does not seem to be passed on.
I tried loading using:
$.ajax("${dataUrl.raw()}",
{
xhrFields: {
withCredentials: true
}, crossDomain: true
}).done(function(data) {
});
But his results the following error:
Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at http://192.168.1.27:9000/carousel/1/data.json. (Reason: CORS header 'Access-Control-Allow-Origin' does not match '*').
Loading it without the xhrFields loads ok, but the user is not logged on, suggesting the cookie is not passed in the request.
I could optionally include the logon credentials in each data request, but I would prefer just to do it once on startup and give use the cookie with a long lifespan.
[edit:]
I tried to add different values for the 'Access-Control-Allow-Origin', but passing in 'file://' which seems the origin in the case of the call from the local file system does not work as to is said to not match, or chromium says the t'null' is not allowed (which technically I think it is because I have nothing after 'file://'.)

In a CORS request the server (http://192.168.1.27:9000) needs to allow the use of sending cookies or else an error will be thrown. To enable this the server needs to respond with the following header
Access-Control-Allow-Credentials: true
You can read more about this header here: https://developer.mozilla.org/en-US/docs/Web/HTTP/Access_control_CORS#Access-Control-Allow-Credentials
In addition, can you serve this page from say localhost? I'm not sure how file:// plays with the CORS headers.
Also, make sure you server is passing along this header
Access-Control-Allow-Origin: *
The * will allow any website but you can scope it to just a single domain.

Related

how to make a cross domain api call using jQuery [duplicate]

I'm trying to load a cross-domain HTML page using AJAX but unless the dataType is "jsonp" I can't get a response. However using jsonp the browser is expecting a script mime type but is receiving "text/html".
My code for the request is:
$.ajax({
type: "GET",
url: "http://saskatchewan.univ-ubs.fr:8080/SASStoredProcess/do?_username=DARTIES3-2012&_password=P#ssw0rd&_program=%2FUtilisateurs%2FDARTIES3-2012%2FMon+dossier%2Fanalyse_dc&annee=2012&ind=V&_action=execute",
dataType: "jsonp",
}).success( function( data ) {
$( 'div.ajax-field' ).html( data );
});
Is there any way of avoiding using jsonp for the request? I've already tried using the crossDomain parameter but it didn't work.
If not is there any way of receiving the html content in jsonp? Currently the console is saying "unexpected <" in the jsonp reply.
jQuery Ajax Notes
Due to browser security restrictions, most Ajax requests are subject to the same origin policy; the request can not successfully retrieve data from a different domain, subdomain, port, or protocol.
Script and JSONP requests are not subject to the same origin policy restrictions.
There are some ways to overcome the cross-domain barrier:
CORS Proxy Alternatives
Ways to circumvent the same-origin policy
Breaking The Cross Domain Barrier
There are some plugins that help with cross-domain requests:
Cross Domain AJAX Request with YQL and jQuery
Cross-domain requests with jQuery.ajax
Heads up!
The best way to overcome this problem, is by creating your own proxy in the back-end, so that your proxy will point to the services in other domains, because in the back-end not exists the same origin policy restriction. But if you can't do that in back-end, then pay attention to the following tips.
**Warning!**
Using third-party proxies is not a secure practice, because they can keep track of your data, so it can be used with public information, but never with private data.
The code examples shown below use jQuery.get() and jQuery.getJSON(), both are shorthand methods of jQuery.ajax()
CORS Anywhere
2021 Update
Public demo server (cors-anywhere.herokuapp.com) will be very limited by January 2021, 31st
The demo server of CORS Anywhere (cors-anywhere.herokuapp.com) is meant to be a demo of this project. But abuse has become so common that the platform where the demo is hosted (Heroku) has asked me to shut down the server, despite efforts to counter the abuse. Downtime becomes increasingly frequent due to abuse and its popularity.
To counter this, I will make the following changes:
The rate limit will decrease from 200 per hour to 50 per hour.
By January 31st, 2021, cors-anywhere.herokuapp.com will stop serving as an open proxy.
From February 1st. 2021, cors-anywhere.herokuapp.com will only serve requests after the visitor has completed a challenge: The user (developer) must visit a page at cors-anywhere.herokuapp.com to temporarily unlock the demo for their browser. This allows developers to try out the functionality, to help with deciding on self-hosting or looking for alternatives.
CORS Anywhere is a node.js proxy which adds CORS headers to the proxied request.
To use the API, just prefix the URL with the API URL. (Supports https: see github repository)
If you want to automatically enable cross-domain requests when needed, use the following snippet:
$.ajaxPrefilter( function (options) {
if (options.crossDomain && jQuery.support.cors) {
var http = (window.location.protocol === 'http:' ? 'http:' : 'https:');
options.url = http + '//cors-anywhere.herokuapp.com/' + options.url;
//options.url = "http://cors.corsproxy.io/url=" + options.url;
}
});
$.get(
'http://en.wikipedia.org/wiki/Cross-origin_resource_sharing',
function (response) {
console.log("> ", response);
$("#viewer").html(response);
});
Whatever Origin
Whatever Origin is a cross domain jsonp access. This is an open source alternative to anyorigin.com.
To fetch the data from google.com, you can use this snippet:
// It is good specify the charset you expect.
// You can use the charset you want instead of utf-8.
// See details for scriptCharset and contentType options:
// http://api.jquery.com/jQuery.ajax/#jQuery-ajax-settings
$.ajaxSetup({
scriptCharset: "utf-8", //or "ISO-8859-1"
contentType: "application/json; charset=utf-8"
});
$.getJSON('http://whateverorigin.org/get?url=' +
encodeURIComponent('http://google.com') + '&callback=?',
function (data) {
console.log("> ", data);
//If the expected response is text/plain
$("#viewer").html(data.contents);
//If the expected response is JSON
//var response = $.parseJSON(data.contents);
});
CORS Proxy
CORS Proxy is a simple node.js proxy to enable CORS request for any website.
It allows javascript code on your site to access resources on other domains that would normally be blocked due to the same-origin policy.
CORS-Proxy gr2m (archived)
CORS-Proxy rmadhuram
How does it work?
CORS Proxy takes advantage of Cross-Origin Resource Sharing, which is a feature that was added along with HTML 5. Servers can specify that they want browsers to allow other websites to request resources they host. CORS Proxy is simply an HTTP Proxy that adds a header to responses saying "anyone can request this".
This is another way to achieve the goal (see www.corsproxy.com). All you have to do is strip http:// and www. from the URL being proxied, and prepend the URL with www.corsproxy.com/
$.get(
'http://www.corsproxy.com/' +
'en.wikipedia.org/wiki/Cross-origin_resource_sharing',
function (response) {
console.log("> ", response);
$("#viewer").html(response);
});
The http://www.corsproxy.com/ domain now appears to be an unsafe/suspicious site. NOT RECOMMENDED TO USE.
CORS proxy browser
Recently I found this one, it involves various security oriented Cross Origin Remote Sharing utilities. But it is a black-box with Flash as backend.
You can see it in action here: CORS proxy browser
Get the source code on GitHub: koto/cors-proxy-browser
You can use Ajax-cross-origin a jQuery plugin.
With this plugin you use jQuery.ajax() cross domain. It uses Google services to achieve this:
The AJAX Cross Origin plugin use Google Apps Script as a proxy jSON
getter where jSONP is not implemented. When you set the crossOrigin
option to true, the plugin replace the original url with the Google
Apps Script address and send it as encoded url parameter. The Google
Apps Script use Google Servers resources to get the remote data, and
return it back to the client as JSONP.
It is very simple to use:
$.ajax({
crossOrigin: true,
url: url,
success: function(data) {
console.log(data);
}
});
You can read more here:
http://www.ajax-cross-origin.com/
If the external site doesn't support JSONP or CORS, your only option is to use a proxy.
Build a script on your server that requests that content, then use jQuery ajax to hit the script on your server.
Just put this in the header of your PHP Page and it ill work without API:
header('Access-Control-Allow-Origin: *'); //allow everybody
or
header('Access-Control-Allow-Origin: http://codesheet.org'); //allow just one domain
or
$http_origin = $_SERVER['HTTP_ORIGIN']; //allow multiple domains
$allowed_domains = array(
'http://codesheet.org',
'http://stackoverflow.com'
);
if (in_array($http_origin, $allowed_domains))
{
header("Access-Control-Allow-Origin: $http_origin");
}
I'm posting this in case someone faces the same problem I am facing right now. I've got a Zebra thermal printer, equipped with the ZebraNet print server, which offers a HTML-based user interface for editing multiple settings, seeing the printer's current status, etc. I need to get the status of the printer, which is displayed in one of those html pages, offered by the ZebraNet server and, for example, alert() a message to the user in the browser. This means that I have to get that html page in Javascript first. Although the printer is within the LAN of the user's PC, that Same Origin Policy is still staying firmly in my way. I tried JSONP, but the server returns html and I haven't found a way to modify its functionality (if I could, I would have already set the magic header Access-control-allow-origin: *). So I decided to write a small console app in C#. It has to be run as Admin to work properly, otherwise it trolls :D an exception. Here is some code:
// Create a listener.
HttpListener listener = new HttpListener();
// Add the prefixes.
//foreach (string s in prefixes)
//{
// listener.Prefixes.Add(s);
//}
listener.Prefixes.Add("http://*:1234/"); // accept connections from everywhere,
//because the printer is accessible only within the LAN (no portforwarding)
listener.Start();
Console.WriteLine("Listening...");
// Note: The GetContext method blocks while waiting for a request.
HttpListenerContext context;
string urlForRequest = "";
HttpWebRequest requestForPage = null;
HttpWebResponse responseForPage = null;
string responseForPageAsString = "";
while (true)
{
context = listener.GetContext();
HttpListenerRequest request = context.Request;
urlForRequest = request.RawUrl.Substring(1, request.RawUrl.Length - 1); // remove the slash, which separates the portNumber from the arg sent
Console.WriteLine(urlForRequest);
//Request for the html page:
requestForPage = (HttpWebRequest)WebRequest.Create(urlForRequest);
responseForPage = (HttpWebResponse)requestForPage.GetResponse();
responseForPageAsString = new StreamReader(responseForPage.GetResponseStream()).ReadToEnd();
// Obtain a response object.
HttpListenerResponse response = context.Response;
// Send back the response.
byte[] buffer = System.Text.Encoding.UTF8.GetBytes(responseForPageAsString);
// Get a response stream and write the response to it.
response.ContentLength64 = buffer.Length;
response.AddHeader("Access-Control-Allow-Origin", "*"); // the magic header in action ;-D
System.IO.Stream output = response.OutputStream;
output.Write(buffer, 0, buffer.Length);
// You must close the output stream.
output.Close();
//listener.Stop();
All the user needs to do is run that console app as Admin. I know it is way too ... frustrating and complicated, but it is sort of a workaround to the Domain Policy problem in case you cannot modify the server in any way.
edit: from js I make a simple ajax call:
$.ajax({
type: 'POST',
url: 'http://LAN_IP:1234/http://google.com',
success: function (data) {
console.log("Success: " + data);
},
error: function (e) {
alert("Error: " + e);
console.log("Error: " + e);
}
});
The html of the requested page is returned and stored in the data variable.
To get the data form external site by passing using a local proxy as suggested by jherax you can create a php page that fetches the content for you from respective external url and than send a get request to that php page.
var req = new XMLHttpRequest();
req.open('GET', 'http://localhost/get_url_content.php',false);
if(req.status == 200) {
alert(req.responseText);
}
as a php proxy you can use https://github.com/cowboy/php-simple-proxy
Your URL doesn't work these days, but your code can be updated with this working solution:
var url = "http://saskatchewan.univ-ubs.fr:8080/SASStoredProcess/do?_username=DARTIES3-2012&_password=P#ssw0rd&_program=%2FUtilisateurs%2FDARTIES3-2012%2FMon+dossier%2Fanalyse_dc&annee=2012&ind=V&_action=execute";
url = 'https://google.com'; // TEST URL
$.get("https://images"+~~(Math.random()*33)+"-focus-opensocial.googleusercontent.com/gadgets/proxy?container=none&url=" + encodeURI(url), function(data) {
$('div.ajax-field').html(data);
});
<div class="ajax-field"></div>
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
You need CORS proxy which proxies your request from your browser to requested service with appropriate CORS headers. List of such services are in code snippet below. You can also run provided code snippet to see ping to such services from your location.
$('li').each(function() {
var self = this;
ping($(this).text()).then(function(delta) {
console.log($(self).text(), delta, ' ms');
});
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script src="https://cdn.rawgit.com/jdfreder/pingjs/c2190a3649759f2bd8569a72ae2b597b2546c871/ping.js"></script>
<ul>
<li>https://crossorigin.me/</li>
<li>https://cors-anywhere.herokuapp.com/</li>
<li>http://cors.io/</li>
<li>https://cors.5apps.com/?uri=</li>
<li>http://whateverorigin.org/get?url=</li>
<li>https://anyorigin.com/get?url=</li>
<li>http://corsproxy.nodester.com/?src=</li>
<li>https://jsonp.afeld.me/?url=</li>
<li>http://benalman.com/code/projects/php-simple-proxy/ba-simple-proxy.php?url=</li>
</ul>
Figured it out.
Used this instead.
$('.div_class').load('http://en.wikipedia.org/wiki/Cross-origin_resource_sharing #toctitle');

AngularJs - Server throwing exception''XMLHttpRequest cannot load the "URL" Response for preflight is invalid (redirect)'

What is the reason the server is returning object as 'undefined' and 'XMLHttpRequest cannot load the "URL" Response for preflight is invalid (redirect).
Flow of app - its just a normal post service sending document details to the server in return should return an object holding various parameters, but its returning 'undefined'
The service for posting the document
fileUpload: {
method: 'POST',
url: config.apiPath + 'employee/service/pushRecords', //this is the URL that should return an object with different set of parameters (currently its returning Error error [undefined])
isArray: false,
params: {},
headers: {
'content-type': undefined
}
},
above service i have used after creating formdata w.r.t document
function registerFormdata(files, fieldName) {
files = files || [];
fieldName = fieldName || 'FileSent';
var returnData = new FormData();
_.each(files, function (file, ind) {
returnData.append(fieldName,file);
});
return returnData;
}
now this is the controller where these services are used
function sendFilesToServer() {
var formData = employeePushService.registerFormdata(directive.dropZoneFile.fileToUpload);
return docUploadService.fileUpload(formData)
.then(function(document) {
// Extra actions but here the server should be returning an object with set of parameters but in browser console its Error [undefined]
}).catch(logger.error);
}
Assuming that the URL target in yout post is correct, it seems that you have a CORS problem, let me explain some things.
I don't know if the server side API it's developed by yourself, if it is, you need to add the CORS access, your server must return this header:
Access-Control-Allow-Origin: http://foo.example
You can replace http://foo.example by *, it means that all request origin will have access.
First, you need to know that when in the client you make an AJAX CORS request, your browser first do a request to the server to check if the server allow the request, this request is a OPTION method, you can see this if, for example in chrome, you enable the dev tools, there, in the network tab you can see that request.
So, in that OPTIONS request, the server must set in the response headers, the Access-Control-Allow-Origin header.
So, you must check this steps, your problem is that the server side is not allowing your request.
By the way, not all the content-type are supported in CORS request, here you have more information that sure will be helpfull.
Another link to be helpfull for the problem when a 302 happens due to a redirect. In that case, the POST response must also include the Access-Control-Allow-Origin header.

Cookie management after 302 redirection with XMLHttpRequest

I'm developing a Firefox OS client for ownCloud. When I try to login and send the user credentials to the server, I need to obtain in response the cookie that I will use to authenticate in ownCloud in each request.
My problem is that as I’ve seen in Wireshark, the cookie is sent in a HTTP 302 message, but I cannot read this message in my code because Firefox handles it automatically and I read the final HTTP 200 message without cookie information in the
request.reponseText;
request.getAllResponseHeaders();
So my question is if there is any way to read this HTTP 302 message headers, or if I can obtain the cookie from Firefox OS before I send the next request, or even make Firefox OS to add the cookie automatically. I use the following code to make the POST:
request = new XMLHttpRequest({mozSystem: true});
request.open('post', serverInput, true);
request.withCredentials=true;
request.addEventListener('error', onRequestError);
request.setRequestHeader("Cookie",cookie_value);
request.setRequestHeader("Connection","keep-alive");
request.setRequestHeader("Content-type","application/x-www-form-urlencoded");
request.send(send_string);
if(request.status == 200 || request.status==302){
response = request.responseText;
var headers = request.getAllResponseHeaders();
document.getElementById('results').innerHTML="Server found";
loginSuccessfull();
}else{
alert("Response not found");
document.getElementById('results').innerHTML="Server NOT found";
}
"mozAnon
Boolean: Setting this flag to true will cause the browser not to expose the origin and user credentials when fetching resources. Most important, this means that cookies will not be sent unless explicitly added using setRequestHeader.
mozSystem
Boolean: Setting this flag to true allows making cross-site connections without requiring the server to opt-in using CORS. Requires setting mozAnon: true, i.e. this can't be combined with sending cookies or other user credentials." [0]
I'm not sure if you're an owncloud developer, but if you are and have access to the server, you should try setting CORS headers. [1] Maybe if you can stand up a proxy server and have your app connect to the proxy server that does have CORS enabled?
There's also a withCredentials property [2] you can set on instances of xhr objects. It looks like it will add the header Access-Control-Request-Headers: "cookies" and send an HTTP OPTIONS request, which is the preflight [3]. So this would still require server side support for CORS. [4]
Though it seems like this shouldn't work based on internal comments [5], I was able to run this from a simulator and see the request and response headers:
var x = new XMLHttpRequest({ mozSystem: true });
x.open('get', 'http://stackoverflow.com');
x.onload = function () { console.log(x.getResponseHeader('Set-Cookie')); };
x.setRequestHeader('Cookie', 'hello=world;');
x.send();
You'd probably want to reassign document.cookie in the onload event, rather than logging it, if the response header exists (not every site sets cookies on every request). You'd also want to set the request header to document.cookie itself.
[0] https://developer.mozilla.org/en-US/docs/Web/API/XMLHttpRequest#XMLHttpRequest%28%29
[1] https://developer.mozilla.org/en-US/docs/Web/HTTP/Access_control_CORS
[2] https://developer.mozilla.org/en-US/docs/Web/API/XMLHttpRequest#Properties
[3] https://developer.mozilla.org/en-US/docs/Web/HTTP/Access_control_CORS#Preflighted_requests
[4] http://www.html5rocks.com/en/tutorials/cors/#toc-making-a-cors-request
[5] https://bugzilla.mozilla.org/show_bug.cgi?id=966216#c2

sending email via XMLHttpRequest no response

I tried to manage editing the template but I'm still not able to send email, I'm creating an subscription box, here's my code so far:
var x= document.getElementById("emailtxt").value;
var uploadFormData = new FormData();
uploadFormData.append("email", x);
var xhr = new XMLHttpRequest();
xhr.open('POST', 'http://realfashionstreet.com/Emailme.php',true);
xhr.onload=function() {
alert(this.status);
if(this.status==200) {
console.log('data sent');
alert(xhr.responseText);
} else {
//alert(this.status);
alert('Something Went Wrong, Try Again Later!');
}
};
/*xhr.addEventListener("load", function () {
document.getElementById('skm_LockPane').className= 'LockOff';
}, false);*/
xhr.send(uploadFormData);
return false;
}
Here's the box I'm getting :
http://realfashionstreet.com
It's just not showing any error or any response and also not sending email, but I think that site template doesn't allow to use php files if anyone have any other idea on how to send email using javascript…
Thanks
You can't for security reasons. See the same origin policy for JavaScript.
There are some workarounds that exploit browser bugs or corner cases, but using them is not recommended.
The best approach is having a server-side proxy that receives Ajax requests, and in turn, sends HTTP requests to other servers. This should be carefully implemented by sanitizing input and whitelisting the types of requests that are sent, and the servers that are contacted.
You're missing the www. in the request, this is causing a cross domain policy violation. This is the error I see in the console.
XMLHttpRequest cannot load http://realfashionstreet.com/Emailme.php. No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'http://www.realfashionstreet.com' is therefore not allowed access. Default.asp:1
Ensure the URLs for the page and the XHR request have the exact same domains. Including subdomains like www

XMLHttpRequest cross domain throws error

I made a 'voting' API for a topsite for the sites registered to use.
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js"></script>
<script type="text/javascript">
var id = 1;
$(document).ready(function(){
$.getJSON("http://mysite.com/index.php?page=vote", { id: id, hasVoted: 'unknown' }, function(data) {
if(data == 2) {
window.location.replace("http://mysite.com/index.php?page=vote&id=" + id);
}
});
});
</script>
Basically, I give the user's their ID and then they put that code in their files.
The site returns a number and upon that, it redirects the user or not to voting.
So, testing on localhost that code throws this error:
XMLHttpRequest cannot load http://mysite.com/index.php?page=vote&id=1&hasVoted=unknown. Origin http://localhost is not allowed by Access-Control-Allow-Origin.
If I use this code:
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js"></script>
<script type="text/javascript">
var id = 1;
$(document).ready(function(){
$.getJSON("http://mysite.com/index.php?page=vote&callback=?", { id: id, hasVoted: 'unknown' }, function(data) {
if(data == 2) {
window.location.replace("http://mysite.com/index.php?page=vote&id=" + id);
}
});
});
</script>
Then it does nothing. It throws no error. ( While data is supposed to be equal to 2 ( When checking that URL directly, it returns 2 ) ).
And, if I try to do a little test, and do alert(data); It throws nothing still.
I'm completely clueless about this. Anything will help.
Well known problem, the origin control of the browser:
A browser doesn't allow you to make ajax requests to 'cross-origin' domains by default. Cross origin means, that either the port or host is different. Therefore you can't send requests to site http://siteB/ while the script to make the requests is hosted on site A.
Simple solution would be to host everything on one domain and make the url relative. If that's not possible, you have to find another way no make cross-origin calls.
Some examples:
JSONP (only GET)
CORS (work's very good with modern browser)
include an ifram + use PostMessage between the windows
proxy script
EDIT:
What I would do, is first allow your API-SERVER some stuff, by setting these headers:
header("Access-Control-Allow-Origin: *");
header("Access-Control-Allow-Methods: POST, GET, OPTIONS");
header("Access-Control-Allow-Headers: Authorization");
Be aware, that this isn't working properly with the Internet Explorer, so you have to use: XDomainRequest. But this doesn't allow you sending headers. Please see my question a couple days ago, if you have to send headers cross-origin

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